The present invention relates to an electric actuator for outputting rotation of an electric motor through a speed reduction mechanism, and particularly to a technique effectively applied to an electric actuator, which is provided with position detecting means for detecting a rotational position of an output shaft and a control board for controlling the electric motor.
An electric actuator is a device such as an electric motor for converting an electrically generated driving force into work such as a mechanical linear or rotational motion or the like. Because the electric actuator has higher energy efficiency and is excellent in controllability as compared with an actuator in which air pressure or hydraulic pressure is used, it is widely used for automobile parts and the like.
As such an electric actuator, for example, there is a known sunroof motor used as a driving source of a sunroof system provided in a vehicle such as an automobile or the like, as disclosed in Japanese Patent Laid-open No. 2001-219742. In this case, the sunroof system has a roof panel, which is guided by a guide rail fixed to a roof of the vehicle and is provided to be openable and closeable. A driving cable having a gear is linked to the roof panel. Meanwhile, the sunroof motor has an electric motor and a worm gear mechanism, whereby a speed of rotation of the electric motor is reduced by the worm gear mechanism and transferred to an output shaft. Also, a driving gear is fixed to the output shaft of the sunroof motor and the driving cable is engaged with the driving gear. By an operation of the sunroof motor, the driving gear actuates the driving cable in an axial direction, so that the roof panel is opened and closed while being pushed and pulled by the driving cable.
As such a sunroof motor, for example, there is one provided with a panel-position detecting mechanism for detecting a position of a roof panel and a controller for controlling an electric motor based on a signal from the panel-position detecting mechanism, in order to stop the actuation of the roof panel when the roof panel is in a fully-open state or a fully-closed state, as disclosed in Japanese Patent Laid-open No. 9-216518 and No. 11-334379. In this case, the panel-position detecting mechanism includes a cam plate having cam teeth on its outer peripheral face and a limit switch slidably contacting with the outer peripheral face of the cam plate, whereby the cam plate rotates in synchronization with an output shaft. When the roof panel comes to a fully-open or fully-closed state, the cam teeth turn the limit switch on from off and the limit switch outputs a position detecting signal. Meanwhile, the controller has a control board, which is provided with a control circuit formed of a plurality of electric circuit elements, and the limit switch is connected to the control board through a lead wire. The control board controls the electric motor based on the position detecting signal from the limit switch.
In such a sunroof motor, the panel-position detecting mechanism and the controller are housed in an actuator case together with the worm gear mechanism, thereby being formed like a unit as a whole.
Because such a sunroof motor is mounted onto a roof of a vehicle, it is desired to miniaturize the sunroof motor. However, in the conventional sunroof motor, since both the limit switch and the control board are fixed in the actuator case, a fixed place of the limit switch to the control board is limited. Therefore, it is difficult to fix the limit switch in the vicinity of the control board to miniaturize the sunroof motor.
An object of the present invention is to improve layout characteristics of a detecting switch relative to a control board to miniaturize an electric actuator.
An electric actuator of the present invention, which has an electric motor, an actuator case fixed to said electric motor, and a speed reduction mechanism housed in said actuator case and reducing a speed of rotation of said electric motor to transmit the rotation to an output shaft, comprises: a detecting switch fixed outside said actuator case and actuated by a cam member operated in synchronization with said output shaft to output a detecting signal in accordance with a rotational position of said output shaft; control means fixed inside said actuator case and having a control board for controlling said electric motor based on said detecting signal from said detecting switch; and a connecting member for electrically connecting said detecting switch and said control board through a connecting through hole provided in said actuator case.
According to an electric actuator of the present invention, said connecting member is a board-side connecting terminal including: a leg, portion fixed to said control board; and a connecting portion projecting outside from said connecting through hole to be connected to a switch-side connecting terminal provided to said detecting switch.
According to an electric actuator of the present invention, said leg portion is formed by bending in a crank shape.
According to an electric actuator of the present invention, said detecting switch is screwed to said actuator case from a direction perpendicular to a connection direction of said switch-side connecting terminal and said connecting portion.
According to an electric actuator of the present invention, a support wall portion facing said board-side connecting terminal is formed integrally with said actuator case on a back side of said connecting portion relative to said connecting direction.
According to an electric actuator of the present invention, said cam member is disposed coaxially with said output shaft, and said detecting switch is in slidable contact with an outer peripheral face of said cam member.
According to an electric actuator of the present invention, said switch-side connecting terminal is connected to said connecting portion by moving said detecting switch away from said output shaft, and said detecting switch is screwed from a direction parallel to an axial direction of said output shaft.
According to an electric actuator of the present invention, said cam member and said detecting switch are covered with a cover engaged with said actuator case.
According to an electric actuator of the present invention, said output shaft is connected to an opening/closing member openably and closably mounted to a roof of a vehicle, and said opening/closing member is opened and closed by rotation of said output shaft.
According to the present invention, the detecting switch is fixed outside the actuator case, and the control means is fixed inside the actuator case, and the detecting switch and the control means are electrically connected through the connecting through hole by the connecting member. Therefore, the layout characteristics of the detecting switch relative to the control board are improved, and the detecting switch can be fixing in the vicinity of the control means, and the electric actuator can be miniaturized.